﻿/************************************************************************

   Extended Silverlight Toolkit

   Copyright (C) 2010-2012 Xceed Software Inc.

   This program is provided to you under the terms of the Microsoft Public
   License (Ms-PL) as published at http://extendedsilverlight.codeplex.com/license

   Please purchase a commercial version of this toolkit if you are using
   it in a commercial product. The commercial versions support the project,
   and also include more features for each control, priority support,
   source code, updates, removed watermark, and a proprietary license.

   Visit http://xceed.com and follow @datagrid on Twitter.

  **********************************************************************/

using Xceed.Silverlight.Data.Utils;

namespace Xceed.Silverlight.Data
{
  internal sealed class ExpansionChangingEventManager : SLWeakEventManager
  {
    #region Static Fields

    private readonly static ExpansionChangingEventManager Instance;

    #endregion

    #region Constructors

    static ExpansionChangingEventManager()
    {
      if( ExpansionChangingEventManager.Instance == null )
      {
        ExpansionChangingEventManager.Instance = new ExpansionChangingEventManager();
        SLWeakEventManager.SetCurrentManager( typeof( ExpansionChangingEventManager ), ExpansionChangingEventManager.Instance );
      }
    }

    private ExpansionChangingEventManager()
    {
    }

    #endregion

    internal static void AddListener( GroupHandler source, ISLWeakEventListener listener )
    {
      ExpansionChangingEventManager.Instance.AddListenerProtected( source, listener );
    }

    internal static void RemoveListener( GroupHandler source, ISLWeakEventListener listener )
    {
      ExpansionChangingEventManager.Instance.RemoveListenerProtected( source, listener );
    }

    protected override void StartListening( object source )
    {
      GroupHandler handler = ( GroupHandler )source;

      handler.ExpansionChanging += this.OnExpansionChanging;
    }

    protected override void StopListening( object source )
    {
      GroupHandler handler = ( GroupHandler )source;

      handler.ExpansionChanging -= this.OnExpansionChanging;
    }

    private void OnExpansionChanging( object sender, ExpansionChangedEventArgs e )
    {
      ExpansionChangingEventManager.Instance.DeliverEvent( sender, e );
    }
  }
}
